“They taste great with a beer”, I had been asking a few friends about their experiences with cicadas and this strange response was not what I was expecting, but there is much about the cicada that is strange and unexpected (the same could be said about some of my friends).
For many people around the world (and wildlife too) the cicada is a valued source of protein. The friend who was suggesting them as a good accompaniment to a beer had just returned from living in Laos, where cicadas are commonly eaten and are considered easy to prepare. Apparently all you have to do is pull the wings and legs off and then drop them in a wok of hot oil. In the Western MacDonnell Ranges in Central Australia there are stories of how Aboriginal children used to collect the newly emerged adults for the old people to eat.
Cicadas are and have been an important introduction to nature for Australian children for generations. You only have to contemplate the visually evocative common names of Australian cicadas to understand this; some local examples are Floury Baker, Cherrynose and Double Drummer. So it is no surprise to discover that some of these names were made by children over 100 years ago.
Much of the myth and mystery of the cicada comes from its extraordinary lifecycle. The 1.5–3 mm eggs are laid into a series of slits cut by the female’s ovipositor in anything from the branch of a tree or shrub to the stem of a grass or herb both living and dead. In two to seven months the eggs hatch and the tiny nymphs drop to the ground and quickly search for a crack or crevice to avoid desiccation or predation.
Once underground they will tunnel in search of a suitable location to excavate a cavity beside a plant root, on which they can feed. As they grow they will moult several times and may also need to move to find a new plant root to feed on. The exact time spent underground for most Australian cicadas is unknown, one of the exceptions is the Greengrocer (Cyclochilae australasiae) that has a nymphal stage of about seven years. The lifecycles of American cicadas are much better known and have nymphal stages lasting 13 and 17 years.
Most people’s experience of the nymphal stage is limited to the empty dried brown skin found on tree trunks, grass stems and fence posts. The emergence of the adult from the nymphal skin takes more than an hour and usually occurs during the first few hours of darkness on a warm evening after rain. Once free of the nymphal skin the wings are pumped full of a greenish watery fluid called haemolymph to expand them, which is then withdrawn to allow them to dry and strengthen.
The song of the cicada is a remarkable thing. And for me, more than any other sound, the song of the cicada is the sound of summer in Australia. The Greengrocer is reputedly the loudest insect on the planet at nearly 120 decibels and the Double Drummer is pretty close to that. Put a few hundred in a tree all calling at once and the noise is not far off the pain threshold.
There are other species of cicada that produce calls of such high frequency and low intensity that they are almost inaudible to the human ear. Some sing during the day, others at dusk and some at both times. However all cicada calls are temperature dependent, that is they will not commence calling until air temperature reaches a certain threshold for their species and it will cease once it drops below that threshold. Only the males call and its primary purpose is to attract a female, though some species have a separate distinct distress call.
I haven’t revealed all the secrets of the cicada here, there just isn’t enough space. If you are interested in finding out more, check out Lindsay Popple’s excellent website.
References and Further Reading:
Moulds MS (1990) Australian Cicadas. New South Wales University Press
Queensland Museum (2007) Wildlife of Greater Brisbane. A Queensland Museum Wild Guide.